A retaining element is known from DE 25 16 635 B1. This retaining element provides the arm in the form of a tube. The tube accommodates a force element in the form of a helical spring that is connected to the lever on the one hand and to the tube on the other hand. The helical spring is subjected to tensile loads and holds the arm in the closed position. When the lid is opened, the arm crosses a dead-centre position. From this position, the helical spring urges the arm into the open position so that the arm is automatically moved into the open position and is held in same. The first lever axis is arranged so that it and the first arm axis are positioned on the slider axis, with the helical spring being tensioned to its maximum. The lever enters the tube through a cut and is curved to be arch-shaped. The lever has a recess that embraces a bearing journal of the first joint. This occurs when the arm is in the position with the helical spring pretensioned to its maximum.